This invention relates generally to exercise equipment, and in particular to stationary elliptical motion striding equipment.
A variety of exercise apparatus exists which allow the user to exercise by simulating a striding motion. Some exercise devices allow a stepping motion. For example, U.S. Pat. No. 5,242,343, entitled xe2x80x9cStationary Exercise Device,xe2x80x9d illustrates an exercise device that includes a pair of foot-engaging links for a striding motion. One end of each foot link is supported for rotational motion about a pivot access, and a second end of each foot link is guided in a reciprocal path of travel. The combination of these two foot link motions permits the user""s foot to travel in an inclined, generally oval path of travel. The resulting foot action exercises a large number of muscles through a wide range of motion. The exercise device includes a pair of bell cranks, similar to the bell cranks used with bicycle pedals, traveling in identical circular paths 180xc2x0 apart. The circular paths each have a fixed diameter, which is a function of the fixed length of the bell crank web. The first end of each foot link is pinned to the outer end of one of the bell cranks, and thus also travels in a circular path of a fixed diameter. The second ends of the foot links are either slidingly or rollingly engaged with a linear track, or suspended by a swinging link arm, such that the rotary motion of the first ends of the foot links and the reciprocating motion of the second ends of the foot links, in combination, result in a reciprocating, pseudo-elliptical foot path for the foot pad positioned between the first and second ends of each foot link and on which a user stands. The fixed resulting foot path is a predetermined, machine-defined path that is variable only by manually changing physical parameters of the equipment. Thus, while the exercise device may provide a foot action that exercises a large number of muscles through a wide range of motion, it confines the range of motion by limiting the path traveled by the first ends of the foot links to the circular path of the bell cranks.
One embodiment of the exercise device of the present invention is distinguished from the known so-called xe2x80x9cellipticalxe2x80x9d motion exercise machines by providing a fore and aft horizontal component of striding motion that is dynamically user-defined, while providing a vertical component of the motion that is maintained on a predetermined vertically reciprocating path. While the user""s foot motion is guided in a generally elliptical path, the present invention provides a dynamically variable stride length, which allows the user to move with a natural stride length, within the range of the manufactured product. Thus, a tall or short user is able to extend or curtail the stride length to match his or her natural stride length, and the stride length desired for the level of exercise being performed. The length of the reciprocating path is dynamically adjusted during the exercise operation without equipment adjustments or stopping the exercise being performed by changes in the length of the stride input by the user at a pair of laterally spaced apart foot engagement members. As the user""s legs move with a longer striding motion or a shorter striding motion during exercise, the equipment automatically compensates by similarly increasing or decreasing the relative length-wise displacement of the two foot engagement members. Thus, in contrast to prior art devices, the length and shape of the reciprocating path followed by the user""s feet is dynamically variable as a function of the user""s input, without changing physical parameters or settings of the exercise machine.
The operation of the two foot engagement members is either dependent or independent depending on the construction of the embodiment of the invention. In other words, the two foot engagement members are either operatively interconnected by an interconnection member, or operatively disconnected from one another for independent fore-aft movement.
Furthermore, one aspect of the invention uses a cam/cam follower arrangement to minimize or soften the jolting accelerations and decelerations associated with known fixed stride-length exercise machines. The cams react in response to the extended or shortened length of a user""s stride.
In several embodiments, a transmission utilizing a speed-up drive mode of resistance and flywheel for inertia is coupled to the reciprocating foot engagement members to further smooth the operation, especially the vertical component of the motion. A resistance to the striding motion may be input under user control to enhance the exercise experience by resisting one or both of the vertical and horizontal components of motion.
According to another aspect of the invention, a first foot engagement member is supported for first and second reciprocating motions within a first substantially vertical plane, and a second foot engagement member is supported for first and second reciprocating motions within a second substantially vertical plane laterally spaced away from the first plane at a convenient distance to accommodate a human user.
In some embodiments of the invention, one of the first and second reciprocating motions of the first foot engagement member is interdependent with respective first and second reciprocating motions of the second foot engagement member with both of its vertical and horizontal components. In other embodiments, interdependency is only with respect to the vertical component. In other words, the length component of the striding motion practiced by one of the user""s legs is independent of the corresponding length component practiced by the user""s other leg during exercise. In other embodiments of the invention, the striding motion practiced is the same with respect to the length component as a result of the two foot engagement members being tied together through an interconnection between the foot engagement members, such that a cooperation or xe2x80x9cdependencyxe2x80x9d is maintained between the reciprocating motions of the user""s two feet during exercise in the horizontal component.
According to one aspect of the invention, the first horizontal component of the reciprocal foot motion is dynamically user-defined by varying the length of the stride input by the user at the respective foot engagement member, without accompanying changes to the physical parameters of the exercise machine. According to the invention, the variation in the length of the stride is infinite, within the physical bounds of the exercise machine as manufactured.
In one embodiment of the invention, the height of the vertical component of the reciprocal foot motion is also dynamically user-defined by varying the height of the stride input by the user at the respective foot engagement members, also without accompanying changes to the physical parameters of the exercise machine. Accordingly, the variation in the height of the stride is also infinite, within the physical bounds of the specific embodiment of exercise machine.